Combined exhaust muffler with spark arrester

ABSTRACT

The present invention relates generally to improvements in mufflers for internal combustion engines and the like, and more particularly to an improved spark arrester device in combination with the chamber of a muffler housing. An embodiment of the invention disclosed herein includes an elongate muffler housing, inlet means associated with the housing for receiving exhaust gases from a source such as an internal combustion engine, stopdown means in the housing for receiving exhaust gases from the inlet means and for directing said gases into a chamber defined by said housing. A unique spark arrester and stop-down means traverses said housing chamber and includes a novel arrangement of restricted openings for directing exhaust gases from said chamber.

United States Patent Nelson Aug. 29, 1972 [54] COMBINED EXHAUST MUFFLER WITH SPARK ARRESTER [72] Inventor: Ralph H. Nelson, Stoughton, Wis. [73] Assignee: Nelson Muffler Corporation,

Stoughton, Wis.

[22] Filed: April 6, 1971 [21] Appl. No.: 131,656

[52] US. Cl ..181/36 C, 181/53, 181/58,

[51] Int. Cl. ..Foln l/08, FOln 3/06 [58] Field of Search ..l81/36 R, 36 C, 58, 69-71, 181/53, 54, 56, 63, 47, 57

[56] References Cited UNITED STATES PATENTS 3,545,179 12/1970 Nelson et al....,' ..l81/58 X 3,462,947 8/1969 NowakJ. ..l81/53 X 3,374,857 3/1968 Hutchins ..181/58 3,009,530 11/1961 Cocklin ..l8l/53 1,150,898 8/1915 Spiegel ..18l/53 UX 1,840,862 l/1932 Webb ..l8l/58 X 2,455,965 12/1948 Wohlberg ..181/58 X FOREIGN PATENTS OR APPLICATIONS 26,860 5/ 1931 Australia ..181/63 Primary ExaminerRobert S. Ward, Jr. Attorney-Olson, Trexler, Wolters & Bushnell ABSTRACT I The present invention relates generally to improvements in mufflers for internal combustion engines and the like, and more particularly to an improved spark arrester device in combination with the chamber of a mufiler housing. An embodiment of the invention disclosed herein includes an elongate muffler housing, inlet means associated with the housing for receiving exhaust gases from a source such as an internal com bustion engine, stop-down means in the housing for receiving exhaust gases from the inlet means and for directing said gases into a chamber defined by said housing. A unique spark arrester and stop-down means traverses said housing chamber and includes a novel arrangement of restricted openings for directing exhaust gases from said chamber.

3 Claims, 5 Drawing Figures PATENTEmuczs m2 Jakw W flJl/eL m/ COMBINED EXHAUST MUFFLER WITH SPARK ARRESTER SUMMARY OF'TI-IE INVENTION In some instances the'provision of a spark arrester in association with a muffler for internal combustion engines is quite essential. In fact, in some of the states the use of a spark arrester is mandatory, particularly in instances where the vehicle is to be used for off-road operation. The space available for installation of a muffler and a sparkarrester. is often quite restricted. It is therefore one of the important objectsof the present invention to provide a, combined mufiler and sparkarrester design which is very compact and. to this end the present invention contemplates the provision of a novel and extremely simple yet efficiently operable spark, arrester device which may be used indirect association with a muffler housing.

More specifically, the invention contemplates the provision of avery practical stator or plate member having a unique arrangement of exhaust egress openings'for effectively arresting sparks and contemporaneously assuring desirable stop-down conditions.

The cross-sectional area of a stop-down is critical in two-cycle engine designs and relates proportionally to the engine size and speed. The present invention contemplates a combined spark arrester which may be produced in various sizes to accommodate the particular engine with which it is to be used.

It is also an object of the present invention to provide a spark arrester arrangement of the type above referred to which is particularly adaptable for use with a twocycle internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWING The foregoing and other objects and advantages will be more apparent from the following detailedvdescrip tion when considered in connection with the accompanying drawing wherein:

FIG. 1 is a central longitudinal sectional view of a muffler equipped with the novel spark arrester contemplated by the present invention;

FIG. 2 is a transverse sectional view of the muffler taken substantially along the line 2-2 of FIG. 1;

FIG. 3 is also a transverse sectional view taken substantially alongthe line 3-3 of FIG. 1;

FIG. 4 is an enlarged fragmentary sectional view taken substantially along the line 4-4 of FIG. 2 more clearly to disclose the specific arrangement of the apertures in the spark arrester plate or stator; and

FIG. 5 is a view of reduced size similar to FIG. 1 illustrating a modified muffler incorporating an additional stop-down feature in association with the apertured arrester plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing more in detail, wherein like numerals have been employed to designate similar parts throughout the various figures, it willbe seen that one embodiment of the invention is incorporated in a muffler designated generally by the numeral l0. The mufller [0 includes an elongate housing 12 providing a chamber 14. Exhaust gases from an internal combustion engine (not shown) are directed through an inlet conduit 16 extending through the wall of the housing 12. From the inlet 16 the exhaust gases are directed into an elongate conical member 18 which defines a chamber 20, having its large extremity closed by an end plate 22. Apertures 24 provided in the member 18 direct exhaust gases from the expansion chamber 20 into the housing chamber 14. It will be noted that the end plate 22 also serves as a closure for the right extremity of the chamber 14. Thus, the conical member 18 with its restricted peripheral openings 24 serves as the initial stop-down for exhaust gases from the inlet conduit 16.

Exhaust gases entering the chamber from the openings 24 flow to the'left, FIG. 1, as indicated by the directional I arrows, toward a spark arrester device designated generally by thenu'meral 26. This spark arrester member 26'is in the form of a sheet metal plate or disc 28 formed with an axially extending peripheral flange 30 which may be secured as by welding to the inner periphery of a conduit 32 of circular cross-section. An annular member or bracket 34 serves to support the conduit 32, in spaced relation with respect to the inner surface of the'housing l2.

Particular attention is directed to the manner in which the combined arrester plate and stop-down device 26 is provided with a plurality of exhaust gas receiving substantiallyradial openings 36 in the plate 28. These openings 36 are preferably, uniformly spaced about a common axis. Sections38 are struck from radial slits in the stator or plate 28 in one direction and sections 40 are struck from said plate in the opposite direction as clearly illustrated in FIG. 4. Thus, as exhaust gases flow from the housing chamber 14 through the openings 36 provided between each pair of oppositely disposed struck-out sections 38 and 40, the direction of flow is altered from axial flow through the housing chamber 14 to a circularor swirling flow into a chamber 42 defined by the conduit 32. In this manner the device 26 serves bothas a spark arrester and as stop-down means.

Exhaust gases from the openings 36 expand into the chamber 42 and then pass through a restricted outlet teristics of the internal combustion engine with which the muffler is to beused. It is a simple matter to provide an apertured plate 28 having an arrangement of apertures best suited for the particular engine with which the muffler is to be used. It should also be understood that while the plate or stator member 28, as shown in FIGS. 1 to 3 inclusive, is adapted for use with an elongate housing chamber, it may be used with equal efficiency with muffler housings of differing sizes and shapes. The elongate housing with the cone-shaped stop-down device is shown as one practical application of applicants unique spark arrester plate or stator.

In FIG. 5 a slightly modified muffler arrangement is shown. The muffler in FIG. 5 is designated generally by the numeral a and the only structural difference between the muffler 10 and the muffler 10a is in the provision of a stop-down device 50 interposed between the cone housing 180 and a spark arrester plate 280 corresponding structurally with the previously described plate 28. The stop-down device 50 includes a plate 52, the central portion of which supports a conduit 54 of restricted size. Constituent parts of the muffler 10a corresponding with similar parts of the previously described muffler 10 are indicated by like numerals bearing the suffix a.

From the foregoing it will be apparent that a muffler equipped with a spark arrester as disclosed herein will function with increased efficiency for its intended purpose. Heretofore it has been common practice to incorporate a separate spark-arresting section with a muffler equipped with the conventional stop-down features. The simplicity of applicants unique apertured stator arrangement may be incorporated as a part of the muffler housing, thereby lending desirable compactness as well as increased efficiency in operation.

lclaim:

l. A muffler for two stroke internal combustion engines and the like including a housing providing a chamber, inlet means associated with said housing for receiving exhaust gases from a source such as a two stroke internal combustion engine, including an elongate conical member positioned within said chamber for receiving exhaust gases from said inlet means, spark arrester and stop down plate means traversing said housing chamber including a plurality of openings of predetermined size and disposition about a common axis to permit the passage therethrough of exhaust gases from the chamber defined by said elongate conical member, and outlet means for receiving exhaust gases which have passed through said openings, struckout portions of the combined spark arrester and stop down plate providing the openings of predetermined size and disposition for receiving exhaust gases from the housing chamber to assure improved operational efficiency of an associated two stroke internal combustion engine.

2. A muffler for internal combustion engines and the like as set forth in claim 1 wherein a predetermined disposition of struck-out portions of the spark arrester and step down plate provide the openings for receiving exhaust gases from the housing chamber.

3. A muffler for two stroke internal combustion engines and the like including a housing providing a chamber, inlet means associated with said housing for receiving exhaust gases from a source such as a two stroke internal combustion engine, including an elongate conical member positioned within said chamber for receiving exhaust gases from said inlet means, spark arrester and stop down plate means traversing said housing chamber including a plurality of openings of predetermined size and disposition about a common axis to permit the passage therethrough of exhaust gases from the chamber defined by said elongate conical member, outlet means for receiving exhaust gases which have passed through said openings, and a predetermined disposition of sections of the spark arrestera dst down late bei str ck la erall 'i o posite direc ns bey nd the un mg pl anes o said plate providing openings for receiving exhaust gases from said housing chamber. 

1. A muffler for two stroke internal combustion engines and the like including a housing providing a chamber, inlet means associated with said housing for receiving exhaust gases from a source such as a two stroke internal combustion engine, including an elongate conical member positioned within said chamber for receiving exhaust gases from said inlet means, spark arrester and stop down plate means traversing said housing chamber including a plurality of openings of predetermined size and disposition about a common axis to permit the passage therethrough of exhaust gases from the chamber defined by said elongate conical member, and outlet means for receiving exhaust gases which have passed through said openings, struck-out portions of the combined spark arrester and stop down plate providing the openings of predetermined size and disposition for receiving exhaust gases from the housing chamber to assure improved operational efficiency of an associated two stroke internal combustion engine.
 2. A muffler for internal combustion engines and the like as set forth in claim 1 wherein a predetermined disposition of struck-out portions of the spark arrester and stop down plate provide the openings for receiving exhaust gases from the housing chamber.
 3. A muffler for two stroke internal combustion engines and the like including a housing providing a chamber, inlet means associated with said housing for receiving exhaust gases from a source such as a two stroke internal combustion engine, including an elongate conical member positioned within said chamber for receiving exhaust gases from said inlet means, spark arrester and stop down plate means traversing said housing chamber including a plurality of openings of predetermined size and disposition about a common axis to permit the passage therethrough of exhaust gases from the chamber defined by said elongate conical member, outlet means for receiving exhaust gases which have passed through said openings, and a predetermined disposition of sections of the spark arrester and step down plate being struck laterally in opposite directions beyond the bounding planes of said plate providing openings for receiving exhaust gases from said housing chamber. 